Shaders: add GenericGL::TextureArrayCoordinates.

doc/changelog.dox

@@ -422,6 +422,8 @@ See also:
     @ref Shaders::Generic::SecondaryJointIds, @ref Shaders::Generic::Weights
     and @ref Shaders::Generic::SecondaryWeights attributes for GPU skinning
     support (see also [mosra/magnum#441](https://github.com/mosra/magnum/pull/441))
+-   New @ref Shaders::GenericGL::TextureArrayCoordinates attribute for shaders
+    accepting three-component texture array coordinates
 -   GPU skinning support in @ref Shaders::FlatGL, @ref Shaders::PhongGL and
     @ref Shaders::MeshVisualizerGL2D / @ref Shaders::MeshVisualizerGL3D (see
     also [mosra/magnum#444](https://github.com/mosra/magnum/pull/444) and

src/Magnum/Shaders/GenericGL.h

@@ -74,9 +74,7 @@ future use, with no attribute definition implemented yet.
 <tr>
 <td>1</td>
 <td colspan="3">
-@ref TextureCoordinates
-
-* *Reserved* --- third component for a layer
+@ref TextureCoordinates / @ref TextureArrayCoordinates
 </td>
 </tr>
 <tr>
@@ -290,11 +288,30 @@ template<UnsignedInt dimensions> struct GenericGL {
     /**
      * @brief 2D texture coordinates
      *
-     * @ref Magnum::Vector2 "Vector2". Corresponds to
+     * @ref Magnum::Vector2 "Vector2". Use either this or the
+     * @ref TextureArrayCoordinates attribute. Corresponds to
      * @ref Trade::MeshAttribute::TextureCoordinates.
      */
     typedef GL::Attribute<1, Vector2> TextureCoordinates;
 
+    #ifndef MAGNUM_TARGET_GLES2
+    /**
+     * @brief 2D array texture coordinates
+     * @m_since_latest
+     *
+     * @ref Magnum::Vector3 "Vector3". Use either this or the
+     * @ref TextureCoordinates attribute. Currently doesn't have a
+     * corresponding @ref Trade::MeshAttribute.
+     * @requires_gl30 Extension @gl_extension{EXT,texture_array}
+     * @requires_gles30 Texture arrays are not available in OpenGL ES 2.0.
+     * @requires_webgl20 Texture arrays are not available in WebGL 1.0.
+     */
+    /* Not naming this TextureCoordinates3D as that's semantically something
+       else, plus texture arrays are not on ES2 while 3D textures are. The name
+       for 3D coords would then be TextureVolumeCoordinates I think. */
+    typedef GL::Attribute<1, Vector3> TextureArrayCoordinates;
+    #endif
+
     /**
      * @brief Three-component vertex color
      *
@@ -541,6 +558,9 @@ struct BaseGenericGL {
     };
 
     typedef GL::Attribute<1, Vector2> TextureCoordinates;
+    #ifndef MAGNUM_TARGET_GLES2
+    typedef GL::Attribute<1, Vector3> TextureArrayCoordinates;
+    #endif
     typedef GL::Attribute<2, Magnum::Color3> Color3;
     typedef GL::Attribute<2, Magnum::Color4> Color4;
     #ifndef MAGNUM_TARGET_GLES2

src/Magnum/Shaders/Test/GenericGL_Test.cpp

@@ -60,6 +60,10 @@ void GenericGL_Test::glslMatch() {
 
     CORRADE_COMPARE(TEXTURECOORDINATES_ATTRIBUTE_LOCATION, GenericGL2D::TextureCoordinates::Location);
     CORRADE_COMPARE(TEXTURECOORDINATES_ATTRIBUTE_LOCATION, GenericGL3D::TextureCoordinates::Location);
+    #ifndef MAGNUM_TARGET_GLES2
+    CORRADE_COMPARE(TEXTURECOORDINATES_ATTRIBUTE_LOCATION, GenericGL2D::TextureArrayCoordinates::Location);
+    CORRADE_COMPARE(TEXTURECOORDINATES_ATTRIBUTE_LOCATION, GenericGL3D::TextureArrayCoordinates::Location);
+    #endif
 
     CORRADE_COMPARE(COLOR_ATTRIBUTE_LOCATION, GenericGL2D::Color3::Location);
     CORRADE_COMPARE(COLOR_ATTRIBUTE_LOCATION, GenericGL3D::Color3::Location);